Modern life involves a large number of transactions that require user authentication. For example, bank customers provide credit/debit cards and enter PINS to obtain cash at ATMs. Retail customers use credit cards—which provide account information and a weak form of user authentication—to buy items at stores. Employees at secure facilities enter pass codes or place their fingers on fingerprint scanners to enter secured entrances. An average person in a modern economy requires a large number of devices or procedures that provide at least some form of user authentication: credit cards, bank cards, key fobs, biometric scanning, pass codes, etc. A person must not only carry a large number of cards and other devices, he or she must search for and remove the correct authentication device before each transaction. In the case of biometric scanners, a user must remember how to use each device and in many cases must wait a significant amount of time while the scanner compares the user's biometric data against a large database of other users' biometric information. In addition to these problems, having a large number of authentication devices and procedures means that individual devices may be easily lost and individual security codes may be easily forgotten. In the case of a lost wallet or purse, replacing the individual authentication devices may require a great deal of effort.
There is therefore a need for improved user authentication technology.